Abstract
We examined endocrine disruptors in diesel exhaust particulates (DEP) emitted from a diesel engine under different engine loads. The antiandrogenic and aryl hydrocarbon receptor (AhR) agonistic activity of DEP extracts (DEPE) were evaluated using PC-3/AR human prostate cancer cells transiently transfected with androgen- or AhR agonist-regulated luciferase reporter plasmids, respectively. The antiandrogenic and AhR agonistic activities were enhanced by higher engine load. The AhR antagonist α-naphthoflavone reversed the antiandrogenic activity of DEPE as seen through a reduction in AhR agonistic activity. The concentrations of polycyclic aromatic hydrocarbons (PAHs) with four or more rings, which are AhR agonists in DEPE, increased with higher engine load. Therefore, the enhanced antiandrogenic activity of DEPE is due in part to the increase in AhR agonists such as PAHs with higher engine load.
